


Our Folly

by BogginsofEternalStench (TeaBagginsFromtheOak)



Category: Supernatural
Genre: Casifer study, I just wanted to explore this dynamic more since we only saw a little bit of it during season 11, Lucifer Being a Massive Asshole While Piloting Cas' Vessel, M/M, One-Shot, Post-Episode: s11e10 The Devil in the Details, Season/Series 11, angsty
Language: English
Status: Completed
Published: 2020-12-18
Updated: 2020-12-18
Packaged: 2021-03-11 03:27:41
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,836
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28148340
Author URL: https://archiveofourown.org/users/TeaBagginsFromtheOak/pseuds/BogginsofEternalStench
Summary: Lucifer has free reign of Castiel's mind after the angel agreed to let the fallen archangel possess his body. With this sudden new insight to his brother's thoughts, he decides to have a little fun with the blue-eyed angel.
Relationships: Castiel/Dean Winchester
Comments: 3
Kudos: 19





	Our Folly

**Author's Note:**

> this is just a character study of sorts, but it's been raging in my head for a minute and I wanted to share it.

Letting Lucifer into his vessel was a much easier process than he had originally thought. A haze went over his mind as Lucifer took control and a dull sense of compliance seemed to take hold of him. He remembers opening his eyes standing in the conference room in the Men of Letters bunker. He wandered for a moment trying to bide his time. He had expected to be pestered by his older brother, but instead he seemed content on driving the vessel. Something Castiel felt inherently uncomfortable with, but at the moment a sense of apathy seemed to take hold of him. It was as if there was a timer going off somewhere in the bunker, but he couldn’t tell from which direction it was coming from. He knew somewhere he would stumble onto the timer eventually, but for right now he preferred to find something to smother the sound of the ringing. He wandered around the little library surrounding the conference table before he found his attention to be tied elsewhere. He wandered to his assigned room within the bunker. He felt unusual in the silence. He could usually hear the sound of Dean’s TV from across the hall, or he could hear Sam’s tapes playing on the opposite wall. He sat on the bed as he looked around the mind of his vessel. He could go wherever he liked, but the thought of leaving the bunker made a pit fill in his stomach. He had been asked out once, and he wasn’t keen on repeating that situation. Where else would he go besides here, in the bunker, in the room that had his own placard on it.

Sure, the placard was a cleanly printed sign tapped to a white board on his door, but it was more than he’d ever had anywhere else. He had barely even managed to get comfortable living anywhere else before he was back here, listening to the grainy sound of an old record player that Sam had fixed up in his spare time and overhearing the boys argue over what vinyl they got to listen to during dinner tonight. It usually ended in an arm wrestle that would be contested until he would arrive to sus out the victor. If he said he was slightly biased, then who would fault him for that. He didn’t know how much time passed while Lucifer controlled his vessel, all time ceasing to exist within the confines of these five lobes. Eventually he found himself wandering across the hall to Dean’s room. He knocked for a moment before the little reminder in the back of his mind reminded him that Dean surely wouldn’t be in here to even give him permission to enter. He still turned the knob with some hesitancy and stood in the doorway as the door swung wide open to reveal the sight he originally was expecting. The empty felt cold and unwelcoming without the usual hunter’s presence. He looked to his right, to the empty bed. He walked forward to put a hand down to let his fingers trail over the duvet of the freshly pressed sheets.

His mind swirled with the prayers he had heard from his hunter while Dean sat on this bed. In a moment of desperation, he even recalled Dean getting on his knees next to the bed to whisper prayers for the angel to hear. For a man who was never taught a conventional way to pray, his voice always rang like a siren call in Cas’ ears.

A sudden feeling washed over Cas as he turned around to see Lucifer standing in Dean’s doorway. For a brief moment the haze he had been in since Lucifer had entered his vessel was lifted as he took in the sight of the smug look on his brother’s face. He looked around the room with a combination of amusement and mock written all over his face. Castiel turned on his heel and faced off with Lucifer. The archangel only seemed to press his face closer to Cas.

“So, this is where you go while I’m away?” Lucifer gave a brief look around before settling his eyes back on Castiel. Castiel felt his finger’s itch for the blade he normally kept in his coat, but he had to remind himself that he had allowed Lucifer to occupy his vessel. “I mean I’m not surprised.” Lucifer took a step inside, ignoring the way Castiel bristled at the movement. He ran his hand along the desk, flicking a pen across the room, very much in the same way a cat would approach any loose item on a table.

“Get out of here, I gave you permission to enter my vessel, but not into my mental space.” Lucifer tutted as he opened the wardrobe on the wall. He rifled through a few before throwing one of the flannels on the ground. Castiel watched as the shirt fell to the ground and he clenched his jaw at the act. While this scene lived entirely in his mind, the thought that Lucifer would tread so uncaringly over his precious memories was aggravating in a way that Castiel hadn’t experienced before.

“It’s hard to resist when your thoughts are so loud, Cassie.” As if out of reflex, Castiel’s back straightened and he flexed the imaginary muscles of his wings. If Lucifer had noticed, he didn’t say anything as he got closer to Castiel at the foot of the bed. “We share a mind you know that, and I’ve seen and heard things from you that even make _me_ blush.” Lucifer gave a shit-eating grin as he leaned into Cas’ face. Castiel kept his stony countenance while Lucifer attempted to goad him. “And I’m the King of Hell, Cassie.” Castiel continued to stare at him blankly as he walked back over to the desk across from Cas.

“I have locked away my memories, so you can’t see them.” Castiel stayed rooted in his spot in case Lucifer tried to do any more redecorating within the room. The shirt still lay in Cas’ peripheral, making him itch to reach out and put it back before it got too wrinkled.

“Sure, most of them. But some of them have a habit of leaking through. Your hold on your memories is subpar at best.” Lucifer crossed his arms over his chest in a bored fashion. He leaned all his weight on Dean’s desk. The pen he dropped earlier rolling at his toe which he kicked, sending it flying towards the lamp behind Castiel. “You know, you and I aren’t all that different.” Castiel let his eyes follow the pen, before snapping back to Lucifer.

“I am nothing like you.” Cas growled at his brother.

“Oh, no Cassie, were basically twins.” Lucifer dropped his hands to grip the edges of the desk. “One in the same you and I.” Castiel recoiled at the insinuation. “You’re the tails to my head, Cassie boy.” Cas’ shoulders relaxed a fraction, the tension in his back becoming too much.

“You are the King of Hell. I am – “He had to stop because although he normally would have identified himself as an angel of the lord, having met his father and lost his grace several times and living as a human would, he didn’t think any of those qualities were that of an angel of the lord anymore. “- a hunter.” He finally settled on that because it was a statement that was becoming apparent the more he rode along with Dean and Sam in the back of the impala.

“No, Cassie, little brother. You are fallen.” Castiel let his façade break for half a second before he replaced it with a look of indifference. “You fall with the rest of them, and then some.” Lucifer look behind Castiel at Dean’s bed. “I’m sure our father would be honored to have you sullied by the righteous man.” Lucifer scratched at the wood of the desk. The sound ricocheting off the walls of the empty bunker. “But you see this is where we are the same. I was kicked out of heaven for loving dad before all his other creations, and you were kicked out of heaven for loving his creations more than even him.” Castiel clenched his fists as he listened to Lucifer who looked like he was thriving off teasing his brother, which he most likely was. “You more so in every way possible it would seem.” Castiel was suddenly flooded with a memory, as if someone had pulled it from the vault in his mind to bring forth right before his very eyes. The sound of panting and flashes of skin played out between them. A muffled voice calling his name and Cas could almost feel the way Dean’s hair slid between his fingertips. The smell of leather was an assault to his nostrils as he took a deep breath at the sight. Castiel looked through the hazy memory to Lucifer, pinning him with a murderous glare.

“Being a filthy human suits you, little brother. Maybe once I’ve gotten rid of Amara, I could take the rest of your grace, so you could finally live out your picturesque human life with your precious Dean Winchester.” Lucifer rolled his eyes. The thought of losing his grace again had Cas nearly throwing himself at his older brother. He didn’t know what kind of damage he could do to the archangel within his own vessel, but he would like to knock that smug look from Lucifer’s face, if only for a moment. “That is if he’d want you after you are no longer useful to him.” Castiel bit down hard on his tongue as he shoved the memory back down into his mind and took long strides to Lucifer. He grabbed his older brother by the shirt and shoved him out of the room. He knew that Lucifer let him, but it felt satisfying none the less to shove him out the door and watch him stumble a bit as he let go of his older brother. Castiel slammed the door in his face and mentally put several complicated locks on the door as he turned around to walk over to the shirt on the ground. He picked up the flannel and ran the fabric between his fingers. He brushed it off before placing it gently back in the wardrobe next to the other ones. He was careful to put it next to the correct code that Dean kept his clothes together in. He carefully shut the wardrobe with a soft click and walked to the foot of the bed again. He sat down with his head in his hands, mentally going through and tightening the hold on his memories, the haze from before seemed to fall over him and before long he had the same apathy to the situation as before. He found that despite the lack of needing to do so, he leaned back and fell asleep at the foot of Dean’s bed.

**Author's Note:**

> Tell me what you guys think. I will be posting a smutty one shot next, but I wanted to post this quick study before I did that. The other one shot will be unrelated to this story.


End file.
